This invention relates to the use of dry valves in lieu of mechanical clutches for effectively disengaging fixed displacement pumps continuously driven by driveshafts connected to engines. More particularly, the invention relates to apparatus for controlling the movement of a dry valve between open and closed positions.
Available actuators for conventional dry valves are either pneumatically or manually operated. Dry valves are typically utilized in mobile vehicles outfitted with pressurized air systems. Most often, dry valves are incorporated into packers of the type associated with refuse vehicles. A prime mover, e.g. the vehicle engine, continuously drives a hydraulic gear pump even while there is no demand on the pump. When closed, the typical dry valve virtually starves the pump inlet of hydraulic fluid, allowing only a small amount of fluid to flow through the pump for purposes of lubrication and cooling.
It would be advantageous to eliminate the need for an air source, along with the weight which results from the pneumatic equipment carried by the vehicle. Typically, pressurized air is moisture-laden and tends to corrode cylinder parts over extended periods of time. In addition, the air occasionally leaks into the hydraulic system and reduces efficiency of the system, or worse causes structural damage to the system.
Finally, there is a significant mobile market segment comprised of vehicles which do not normally have air supply equipment, but which would benefit from the use of hydraulic pumping systems which include dry valves. This invention addresses the latter market segment.